mama grizzly

Noun

 * 1) A female grizzly bear currently rearing one or more cubs.
 * 2)  A woman, especially a mother, who is extremely protective of a child or children.

Usage notes
Though mama bear has been used in the sense of "a woman who is extremely protective of a child or children" since at least the 1990s, use of the term mama grizzly in the same sense was popularized by U.S. politician Sarah Palin, who began using it to refer to herself in 2008. Palin's use of the term later broadened to apply to female candidates she supported in the 2010 U.S. midterm elections.